Phylogenetic analysis

Multiple sequence alignment was built using ClustalW using 152, 149 and 86 sequences identified as Cyt c ₆, Cyt c _6BC or Cyt c _6D, respectively ( Supplementary Table 1 ). Sequence identification was performed using the CyanoOmicsDB database (Zhou et al., 2021). Genome comparison analysis performed using the bioinformatics tools available on the online platform Biocyc (Karp et al., 2019; Karp et al., 2020). Phylogenetic tree was constructed by maximum likelihood method with Geneious version 2023.0 created by Biomatters (https://www.geneious.com), inferred using a neighbour-joining algorithm and Jukes-Cantor as the genetic distance model, using the Bootstrap (n = 100) method (Felsenstein, 1985).